This is by far the type of spell I cast most often.  Success is important to everyone and asking for some help isn't wrong.  Just be clear on what you're asking for.  If it's a test or a upcoming event at work, just think on what you have to do.  Then decide on what kind of help you need.  You don't have to be specific but sometimes you'll want to be.
 

TOOLS:
                Water
                Salt
                Hand Held Fan or Feather,
                Candle
                Quartz Crystal

Note that all these items should be purified before you use them.
 

MOON TIME:  Full
 
 
 
 

1.  Assemble your tools and cast your Circle as usual.  You don't have to do anything different yet so you could, if you like do other things before you begin the spell begins.  Once the Circle is cast, meditate for a few moments on what you want to do.  This will fix the purpose in your mind.

2.  If your tools are not purified, then do so now.  You may also wish to dedicate them to the God and Goddess.  Should you have already purified them, then light the candle and lay out the other items.  The water, salt, fan/feather and candle represent the elements.  The crystal is the focus of the spell.  A focus is something that ties the spell to you and what you want.  During the purification process you might wish to attune the crystal energies to you.  Do so by holding it and becoming accustomed to it.

3.  Take the crystal and lay it in the salt.  Say;

        By the power of the Earth I attune this crystal
        By the power of the Earth may my will be carried out.
        By the power of the Earth so mote it be.

4.  Repeat this process with each 'element'.  You may wish to call the elements in the order that you call them when you cast a Circle.  If not, then call them in whatever order you wish to.  Just make sure that you focus on your intent!

5.  Finally, take the crystal and lay it on the alter between your representations of the God and Goddess.  Addressing both the God and Goddess, tell them of your need.  Call for their blessing and ask that while you hold the crystal, that your spell work.  If you don't wish to keep the crystal with you, keep it on the alter and instead ask that while the crystal is on the alter, that the spell function.

6.  While this spell can be a general ongoing spell, it will need to be renewed.  The renewal process is very important and I'd suggest that you first cast this spell during a full moon and then repeat the spell every full moon, for as long as you wish to keep it.

7.  If you do not wish to just let the spell fade, then request of the elements and God and Goddess that the spell end.

As you can see, this spell can be great for general help as well as more specific things.  The crystal can also be substituted for other stones that work for success.  Experiment and find what works best for you.